Effect of block rotation on fault sealing: An example in Dongpu sag, Bohai Bay basin, China
Por:
Chen S., Xu S., Wang D., Tan Y.
Publicada:
1 ene 2013
Resumen:
Pre-existing faults or early formed faults may be reactivated or locked
in subsequent evolution in a rift basin. The reactivation or sealing of
a fault affects sedimentation in the related fault block, and in turn
controls the accumulation of oil and gas. Based on fault mechanics of
reactivation, this paper established equations denoting the angle range
of the reactivated faults or frictional sliding faults by using Mohr
stress circles. The results were applied to explain the sealing property
of pre-existing faults or early formed faults in Dongpu sag. In the
Dongpu sag, reactivation or sealing of the faults in fault blocks is
supposed due to the rotation of the fault block which was caused by the
activity of high order faults. For quantitative calculation of dip range
for activated faults, the sum of the maximum and minimum principal
stresses were determined by acoustic emission experiment based on the
Kaiser effect of rocks, and the cohesion and inner frictional angle of
rocks were measured by rock physical experiment. The calculations show,
when the dips of early formed faults are from 87 to 45, the faults will
remain activation in the subsequent deformation. Otherwise, the faults
will be locked as sealing faults. The results of petroleum exploration
show that the peak dips of sealing faults are from 36 to 40, and the
most of sealing faults are those with dip angles less than 46-50. These
results indicate that a shallower fault is of better sealing property in
oil and gas reservoirs than a steeper fault in Dongpu sag. (C) 2012
Elsevier Ltd. All rights reserved.
Filiaciones:
Chen S.:
State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing 102249, China
College of Geosciences, China University of Petroleum, Beijing 102249, China
Xu S.:
Univ Nacl Autonoma Mexico, Ctr Geociencias, Queretaro 76001, Qro, Mexico
Wang D.:
Exploration and Development Research Institute, Sinopec Zhongyuan Oilfield Company, Puyang 457000, China
Tan Y.:
Exploration and Development Research Institute, Sinopec Zhongyuan Oilfield Company, Puyang 457000, China
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